Pivotal bearing arrangement for electromagnetic operator



Aug 17, 1965 w. J. RICHERT 3,201,541 PIVOTAL BEARING ARRANGEMENT FOR ELECTROMAGNETIC OPERATOR Filed May 15, 1963 s; I Tm 23M \3 22 /3 7 I8 ,9 l3 8/ INVENTOR Walter J. Richert FIG .6.

BY M 4 ATTORNEY;

extend through those openings.

United States Patent 3,291,541 PWUTAL BEARENG ARRANGEMENT FOR ELEQTRGMAGNETE OPERATOR Walter Johannes l-dchert, Princeton, Ind, assignor to American Machine and Foundry Company, a corporation of New dersey Fiied May 15, 1963, Ser. No. 280,517 7 Claims. (Cl. 200-87) This invention relates to electromagnetic relays of the type wherein a pivoted armature rests on a bearing edge presented by a portion of the frame and is held thereagainst by the combined action of a biasing spring and either the movable spring contact arm (or arms) or the force of the electromagnet, depending upon the operational stage of the relay, there being no rotary bearing to positively constrain the pivotal axis of the armature to a precise position. An example of such a relay is seen in -U.S. Patent No. 3,051,804, issued August '28, 1962, to Lewis H. Mayer.

In relays of this type, the portion of the frame which presents the bearing edge for the armature is frequently provided with projections which are spaced lengthwise of the bearing edge. The armature body has a corresponding number of spaced openings through which the projections extend when the armature is in place. The openings in the armature are materially larger than the cross-sectional dimensions of the projections, so that some freedom of movement is allowed the armature transversely of the bearing edge.

When the relay is new, so that face of the armature which engages the bearing edge is smooth, the armature is allowed the full freedom of movement provided by the difference in transverse dimensions between the openings in the armature body and the projections which When the relay has een operated through several hundred thousand cycles of operation, however, there is a tendency for the parts to become worn and, particularly, for the armature to "be roughened, or even grooved, in that area where the armature body engages the bearing edge. The results of wear tend to restrain movement of the armature transversely of the bearing edge, even though such movement is provided for by the fact that the openings in the armature body are larger than the projections which they accommodate. As a result of roughening or grooving of the armature body, and other factors which tend to develop frictional and binding forces, it occasionally happens that, after long use of the relay, the armature becomes stuck or bound in its energized position, with the appropriate spring forces then being inadequate to pivot the armature back to its deenergized position once the electr-omagnet is deenergized.

The armature body is usually made from magnetic sheet metal of material thickness and the openings therein are provided by punching or like metal working operations in such fashion that the walls of the openings are flat and normal to the faces of the armature. The projections provided on the frame portion which presents the bearing edge also have flat side walls, and it will be understood that jamming or binding of the armature can occur at any time that a flat wall of one of the openings is maintained in firm contact with a corresponding flat side wall of one of the projections. So long as the face 'of the armature body which engages the bearing edge is smooth and uninterrupted, there is usually sufiicient freedom of movement to allow the armature to pivot even though it i initially in direct engagement with one or all of the projections. When the surface of the armature becomes roughened or grooved, however, there is an increasing tendency for the frictional forces at the bearing edge to be so great that, once a side of an opening in the dfiilifi il Patented Aug. 17, P385 armature is in flush engagement with the corresponding projection, the armature does not shift transversely of the bearing edge to allow free pivotal movement.

A general object of the present invention is to provide a relay of the type described wherein the tendency of the armature to stick in its energized position after prolonged operation of the relay is markedly reduced or eliminated so that the operational life of the relay is greatly increased.

Another object is to provide an improved pivotal bearing and mounting arrangement for the armature of a relay of the type described.

In order that the manner in which these and other objects are achieved in accordance with the invention can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

FIG. 1 is a side elevational view of a relay constructed in accordance with one embodiment of the invention;

FIG. 2 is an end elevational view (from the left, as viewed in FIG. 1) of the relay of FIG. 1;

FIG. 3 is a transverse sectional view taken on line 1373, FIG. 1, showing the armature of the relay in top P FIGS. 4 and 4a are fragmentary enlarged sectional views taken on line 4-4, FIG. 3;

FIGS. 5 and 5a are fragmentary enlarged sectional 'views taken on line 55, FIG. 3; and

FIG. 6 is a fragmentary enlarged sectional view taken on line 66, P16. 3.

Referring now to the drawings in detail, the relay of this embodiment of the invention includes an L-shaped field member or frame 1 formed of rigid magnetic sheet material and having a pair of mutually perpendicular legs 2 and 3, leg 2 serving as a support or base on which an electromagnet is mounted. The electromagnet 4 includes T-shaped core 5 with the cross-bar of the T of the core constituting the exposed pole piece 6 of the electromagnet, while the stem of the T extends axially through the coil and is rigidly secured to the frame leg in order to mount the electromagnet on the frame.

The free end of frame leg 3 constitutes the portion of the frame which presents the bearing edge for pivotal mounting of the armature. As will be clear by comparison of FIGS. 1, 2 and 6, the free end of leg 3 has a wide, centered notch so as to provide two projections 7 which extend each from a different end of the surface S 'which defines bearing edge 8. It will be noted that each of the projections 7 lies in the plane of frame leg 3 and constitutes an extension of a different side edge portion thereof. As seen in FIGS. 4-6, the surface 8' extends parallel to the line of intersection between frame legs 2. and 3 but slants toward the electromagnet 4 and leg 2, the bearing edge 8 being defined by the intersection between surface 8' and face 23' of frame leg 3.

The armature of the relay, indicated generally at 9, is formed from rigid magnetic sheet metal and includes a generally rectangular flat main body portion it? and a pair of dependent tails if. The tails iii are spaced apart one edge of body it? and a projection i2, lying in the same plane as body it, is provided midway between the two tails.

Body portion lid of the armature is provided with two spaced openings 13 of such size, shape and disposition as to accommodate the two projections 7 of frame leg 3. In addition, body 19 of the armature includes an opening 14 disposed midway between the two openings 13 and extending into projection 12. The body it of the armature can be considered .as having a center line, indicated at 15 in FIG. 3, which extends at right angles to the pivotal axis of the armature in the assembled relay. The

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two openings 1L3 are equidistant from center line 15, while opening M is centered on the center line.

Each opening 13 is in the form of a regular trapezoid with two parallel sides 16 and i7 and two divergent sides 18 and 19. The two openings 13 are identical. Sides In of the two openings are precisely aligned with each other so as to extend along a common line at right angles to center line 15. P or each opening, sides 13 and 19 diverge away from side 16.

Opening 14 includes a rectangular portion having a straight side 2t) which slants upwardly and away from bearing edge is (considering the armature to be in place and the relay to be disposed in upright position as illustrated) toward the axis of the electromagnet. Side 269 and face 22 of the armature intersect in a line, indicated at 2d, which extends in precise alignment with sides 16 of openings 13. The side of the rectangular portion opposite side fail is interrupted by a tapered notch 2d which is centered on center line 15.

As seen in FIGS. 1, 2, 3 and 6, armature 9 is placed with face 22 thereof directed toward pole piece 6 and in direct engagement with hearing edge 8. Projections '7 extend through openings 13. The length of sides 16 of openings 13 is substantially equal to the width of the side faces 23 of projections '7, faces 23 being on the side of frame leg 3 opposite electromagnet 4. Accordingly,

the armature can occupy a position with sides 16 of openings 13 both in direct engagement With the respective faces 23 of projections 7. The opposite faces 24 of projections 7 are then spaced from edges 17 of openings 13 by a distance y, FIG. 3, assuming that the armature body fit is at right angles to frame leg 3 so that the engagement between sides in and faces 2.3 is flush.

Fixed toframe leg 2 is a contact and terminal block or header 25 of insulating material. Header 25 carries a first series of fixed contacts 26, arranged in a line parallel to hearing edge 8, and a second series of fixed contacts 27 also arranged in a line parallel to hearing edge 8.

Secured to the face of armature 'body itl which is opposite the electromagnet is a movable contact set comprising spring arms 23 each carrying at its free tip a pair of opposed contact buttons 29. The disposition of the movable contact set is such that, when the armature is disposed on bearing'edge 8 with openings 13 accommodating projections '7, spring arms 28 extend between fixed contact series 26 and 27 in such fashion that, as a result of pivotal movement of the armature on bearing edge 8,

a contact button 29 carried by each spring arm can be brought into engagement with a fixed contact.

Mounted on frame leg 3 is a generally T-shaped bracket 39. Bracket 3% is of relatively thin, resilient, non magnetic sheet metal and is secured to the frame by a pair of tabs 31 which are bent to extend through suitable notches in the edges of leg 3. The elongated stem 32 of bracket extends along surface 23' of'leg 3 past bearing edge 8 and through opening 14, terminating in a tip 33 bent at right angles to the stem so as to constitute means for retaining the armature. Crossabar portion 3.4 of the bracket is disposed between armature tails 1d and leg 3 so that, whenthe armature is pivoted away from pole piece 6, the tails 11 cannot come into direct engagement with the frame. Stem 32 is centered on leg 3 and, at the end of the bracket opposite tip 353, there isprovided an ear 35 which projects away from leg 3. A helical tension spring 3% has one of its ends hooked 21 of opening M opening in ear 35,

through notch and its other end hooked'through an so that the spring biases the armature pivotally on bearing edge a; in a direction to engage movable contacts '29 with fixed contacts of series 2 6, Thus, springfid biases the armature to its deenergized position,

seen in FIGS. 4a and 5a.

Upon energization of electromagnet 4, armature body 10 is actuated magnetically into engagement with pole piece 6, so that the armature is then in its energized position, seen in FIGS. 1, 4 and 5. The face of pole piece 6 of bracket 3% normally engages face 23.

-then'tend to prevent toward its deenergized was deactivated. This would occur because, under th .in the present invention and the intersection of the surfaces defining bearing edge 8 lie at least substantially in a common plane parallel to the base leg 2 of the frame. Hence, when the armature is in its energized position, with face 22 engaging both bearing edge 8 and pole piece s, armature body it is at least substantially parallel to frame leg 2.

Since sides 16 and 2th of openings 13 and 1d are all mutually aligned, and since faces 2310f projections 7 he in the plane of faceP-S' of frame leg 3, armature body iii can be disposed as seen in engaging faces 23 and with the intersection 2d of side 26) and face 22 lying in the plane of face 23. Stem 32 Hence, stem 32 engages at least the edge of side Ztl defined by intersection Zil and resiliently holds the armature body in the position seen in FIG. 3, with sides 16 of openings 13 directly engaging faces 23 of projections 7. When the armature is in deenergized position, as seen in FIG. 5a, stem 32 engages side 20 in flush relation, because of the angular disposition of side 29 relative to the plane of armature body iii. In the energized position of the armature, as seen in FIG. 5, stem 32 engages only the edge defined by intersection 263'. Since FIGS. 5 and 5a represent the limits of the pivotal movement allowed armature 9, it is evident that, in engaging stem 32, the armature rocks on the edge defined by intersection 2%,

- When the armature is in its energized position, sides 16 of openings 13 are in flush engagement with faces 23 of projections 7 as seen in FIG. 4. Since bracket 36 urges the armature in a direction to maintain engagement of sides 15 with projections 7, and since the armature is held in engagement with hearing edge 8 by spring 36, pivotal movement of the armature toward its deenergized position occurs about the axis which includes bearing edge 3 and the intersections between sides 1 6 and armature face 22, as will be clear from comparison of FIGS. 4 and 4a. Thus, even though the engagement between sides 16 and faces 23 is flush, as seen in FIG. 4, when the armature is in its energized position, such flush engagement in no way interferes with pivotal movement of the armature toward its deenergized position. In fact, the 'nrtersections between sides 16 and armature face 22 constitute auxiliary bearing edges which are held in engagement with leg 3 by the biasing force of spring stem 32.

In this connection, it is particularly important to note that, were the armature allowed to shift transversely of the bearing edge until sidesl7 of openings 13 engaged faces 24 of projections 7 in flush relation, with the armature in its energized position, such flush engagement would pivotal movement of the armature position when the electromagnet biasing action of spring 36, the armature body portion" would be in engagement both with hearing edge 8 and the intersection between sides 1'7 and the face of body portion 10 opposite face 22. Accordingly, it will be understood that the alignment of sides 16 with intersection 26', and the biasing action of stem 32 of bracket 39, are important features of the relay.

Sides 18 and 19 of openings 13 are made divergent, rather than being parallel in the manner hereinbefore employed'in relays of this type. In this'connection, I have found that, when a relay of this type is made with sides 18 and 19 parallel and at right angles to the pivotal axis of the armature, there is a tendency, because of the methods of manufacture necessarily employed, for the corners defined by sides to and it; and 16 and 1% to be filleted, rather than being true right-angle corners. As a result, in prior-art relays of this type, straight-line engagement of the armature with the corresponding projections, in the fashion seen in FIG. 4a, usually was not achieved. Rather, the surfaces corresponding to sides 16 would engage the filleted or rounded corner in a point contact and, because of the FIG with the sides 1-6 rounded nature of the opening, there was a distinct tendency for the armature to bind on the projections corresponding to projections 7 seen herein. To overcome this difficulty in accordance with the invention, sides 1 and 19 are made to diverge away from the adjacent surfaces of the projections 7 so that, even though the openings 13 may not be initially centered precisely on projections 7 as the armature is installed, the divergent sides 18 and 19 positively guide the armature to a centered position in which sides 16 engage projections 7 in the manner illustrated in FIGS. 4 and 4a, depending upon the pivotal position of the armature.

From the foregoing, it will be understood that all of the features of the invention coact to maintain the armature in a predetermined position on bearing edge 8, with movement of the armature transversely of the bearing edge being minimized. This position is such that the edges defined by the intersections of sides 16 and face 22 are kept in contact with surfaces 23 of projections 7 at bearing edge 8, and sides 17 of openings 13 are not allowed to directly engage faces 24 of projections 7 when the armature is in its energized position.

Though one particularly advantageous embodiment of the invention has been chosen for illustration, it will be understood that various changes and modifications can be made therein without departing from the scope of the invention, as defined in the appended claims.

What is claimed is:

1. In an electromagnetic operator of the type described, the combination of an electromagnet including an exposed pole piece;

a fiat frame member disposed beside said electromagnet and having an end portion extending in the same direction as said pole piece, said end portion being provided with a first straight bearing edge spaced laterally from said pole piece, and

- a projection extending at right angles to said first bearing edge,

said projection havinga side surface directed away from said electromagnet,

said first bearing edge lying at least substantially in the plane defined by said side surface;

a magnetic armature having a flat body portion, said body portion being provided with an opening through which said projection extends,

one face of'said body portion being disposed in pivotal engagement with said first bearing edge, said first bearing edge pivotally supporting said armature for movement between an energized position and a deenergized position,

said body portion of said armature being of material thickness,

said opening having a straight side adjacent said side surface of said projection, said straight side intersecting said one face of said body portion to define a second bearing edge,

the shape and dimensions of said opening being such that said opening loosely surrounds said projection;

resilient means connected to said armature and biasing the same both pivotally, about said first bearing edge in a direction toward deenergized position, and rectilinearly, in a direction transverse to said first bearing edge to maintain said straight side engaged with said side surface of said projection, said electromagnet being operative to pivot said armature .to said energized position; and

resilient stop means, said stop means being so constructed and arranged as to resiliently oppose th pivotal biasing effect of said resilient means when said armature is in said deenerg-ized position,

said first bearing edge and said pole piece being so disposed that, when said armature is in said energized position, said second bearing edge is engaged with said side surface of said projection and is in at least substantial alignment with said first bearing edge.

2. An electromagnetic operator in accordance with claim 1 and wherein said resilient means includes a leaf spring engaging a straight edge presented on said armature body portion in substantial alignment with said straight side of said opening.

3. An electromagnetic operator in accordance with claim 1 and wherein said opening is in the form of a regular trapezoid and said straight side of said opening is the shorter of the two parallel sides of the trapezoid.

4. An electromagnetic operator in accordance with claim 1 and wherein said armature is provided with a second opening;

said resilient means includes a leaf spring extending along the side of said frame member which is directed away from said electromagnet, said leaf spring projecting through said second opening in said armature,

said second opening having a straight side which is parallel to said bearing edges and which slants toward the axis of said electromagnet and away from said electromagnet,

said straight side of said second opening intersecting said one face of said armature body portion in a straight line which is engaged by said leaf spring.

5. In an electromagnetic operator of the type described,

the combination of an electromagnet presenting an exposed pole face;

a fiat frame member disposed beside said electromagnet and having an end portion extending in the same direction as said pole face is directed, said end portion being provided with a notch defining an elongated straight surface extending across said frame member, and

two projections located each at a different end of said elongated straight surface and both extending in the plane of said frame member,

said projections each having a side surface directed away from said electromagnet, said side surfaces lying in the plane of the face of sai frame member which is directed away from said eletromagnet,

said elongated straight surface provided by said notch slanting toward said electromagnet in such fashion that the plane in which said straight surface lies passes behind said pole face, said elongated straight surface intersecting said face of said frame member to present a first straight bearing edge which is at least substantially in the plane defined by said side surfaces of said projections;

a magnetic armature having a flat body portion provided with two spaced openings through which said projections respectively extend,

one face of said body portion being disposed in pivotal engagement with said first bearing edge and said first bearing edge pivotally supporting said armature for movement between an energized position and a dcenergized position,

said body portion of said armature being of material thickness,

said two openings each having a straight side adjacent said side surface of the corresponding one of said projections, said straight sides of said two openings being aligned with each other and each intersecting said one face of said armature body portion to define an auxiliary bearing edge,

the shape and dimensions of each of said openings being such that said openings loosely surround said projections,

said armature body portion also being provided same pivotally, about said first bearing edge in a direction toward said deenergized position;

a leaf spring secured to said frame member and extending along said face of said frame member and projecting through said third opening to engage the straight side of said third opening and bias the armature in a direction urging said auxiliary bearing edges into engagement withsaid side surfaces of said projections; and

resilient stop means, said means being so constructed and arranged as to resiliently oppose the pivotal biasing efiect of said spring when said armature is in said deenergized position,

said first bearing edge and said pole face being so disposed that, when said armature is in saiden'ergized position, said auxiliary bearing edges are engaged with said side surfaces of said projections and are in at least substantial alignment with said first bearing edge. a

6. In an electromagnetic operator of the typedescribed,

the combination of an electromagnet having an exposed pole piece;

a frame member disposed beside said electromagnet and having an end portion extending in the same direction as said pole piece, said end portion having a first straight bearing edge spaced laterally from said pole piece, and a projection extending transversely from said bearing edge; a magnetic armature having a fiat body portion of material thickness, said body portion being provided with an opening through which said projection extends, I Q

one face of said body portion being disposed in pivotal engagement with said first bearing edge, said opening having a straight side which intersects said one face of said body portion to define a second'bearing edge, e the shape and size of said opening being such that said opening loosely surrounds said projection; resilient means biasing said armature pivotaliy'about said first bearing edge in a direction away from said pole piece; means biasing said armature transversely of said first bearing edge in a direction toward said electromagnet,

said straight side of said opening being so disposed as to be urged into engagement with said projection as a result of such transverse bias of said armature; and

actuating means operated by pivotal movement of said armature about said first bearing edge and including means opposing said resilient biasing means to define a deenergized' position for said armature, said electromagnet being operative to pivot said armature, against the biasing force of said resilient biasing means, into an energized position,

the relative positions of said first and second bearing edges being such that said second bearing edge remains in engagement with said projection throughout pivotal movement of said armature between said energized and deenergized positions.

the combination of 5 an electromagnet having an exposed pole piece;

a frame member disposed beside said electroinagnet and having an end portion extending in the same direction as said pole piece, said end portion having a first straightbearing edge spaced laterally from said pole piece, and

a projection extending transversely from said bearing edge;

a magnetic armature having a fiat body portion of material thickness, said body portion being provided with an opening having a straight fiat side wall and through which said projection extends,

one face of said body portion being disposed in pivotal engagement with said first bearing edge,

said side wall intersecting said one face of said body portion to define a second bearing edge,

the width of said opening in a direction normal to said second bearing edge being substantially greater than the corresponding transverse dirnension of said projection;

biasing means connected to said armature and operative to bias the same pivotally, about said first bearing edge in a direction away from said electromagnet, and also transversely of said first bearing edge to maintain said second bearing edge in engagement with said frame member; and

actuating means operated by said armature and including means opposing such pivotal bias to define a deenergized position for' said armature, said electromagnet being operative to pivot said armature against such pivotal bias to an energized position,

said first bearing edge being so disposed on said frame member that said second bearing edge is in at least substantial alignment with said first bearing edge.

References Cited by the Examiner UNITED STATES PATENTS 3/46 Iglehart 200 87 2/56, Bogue et a1 3l7l98 4/59 Sauer 317-l98 7/59 Brunicardi 200-87 11/59 Neumann 20087 8/62 Mayer 200-87 4/64 Sebesta Q 3l7-198 ROBERT K. SCHAEFER, Acting Primary xaminer.

7. In an electromagnetic operator of the type described, 

1. IN AN ELECTROMAGNETIC OPERATOR OF THE TYPE DESCRIBED, THE COMBINATION OF AN ELECTROMAGNETIC INCLUDING AN EXPOSED POLE PIECE; A FLAT FRAME MEMBER DISPOSED BESIDE SAID ELECTROMAGNET AND HAVING AN END PORTION EXTENDING IN THE SAME DIRECTION AS SAID POLE PIECE, SAID END PORTION BEING PROVIDED WITH A FIRST STRAIGHT BEARING EDGE SPACED LATERALLY FROM SAID POLE PIECE, AND A PROJECTION EXTENDING AT RIGHT ANGLES TO SAID FIRST BEARING EDGE, SAID PROJECTION HAVING A SIDE SURFACE DIRECTED AWAY FROM SAID ELECTROMAGNET, SAID FIRST BEARING EDGE LYING AT LEAST SUBSTANTIALLY IN THE PLANE DEFINED BY SAID SIDE SURFACE; A MAGNETIC ARMATURE HAVING A FLAT BODY PORTION, SAID BODY PORTION BEING PROVIDED WITH AN OPENING THROUGH WHICH SAID PROJECTION EXTENDS, ONE FACE OF SAID BODY PORTION BEING DISPOSED IN PIVOTAL ENGAGEMENT WITH SAID IRST BEARING EDGE, SAID FIRST BEARING EDGE PIVOTALLY SUPPORTING SAID ARMATURE FOR MOVEMENT BETWEEN AN ENERGIZED POSITION AND A DEENERGIZED POSITION, SAID BODY PORTION OF SAID ARMATURE BEING OF MATERIAL THICKNESS, SAID OPENING HAVING A STRAIGHT SIDE ADJACENT SAID SIDE SURFACE OF SAID PROJECTION, SAID STRAIGHT SIDE INTERSECTING SAID ONE FACE OF SAID BODY PORTION TO DEFINE A SECOND BEARING EDGE, THE SHAPE AND DIMENSIONS OF SAID OPENING BEING SUCHA THAT SAID OPENING LOOSELY SURROUNDS SAID PROJECTION; RESILIENT MEANS CONNECTED TO SAID ARMATURE AND BIASING THE SAME BOTH PIVOTALLY, ABOUT SAID FIRST BEARING EDGE IN A DIRECTION TOWARD DEENERGIZED POSITION, AND RECTILINEARLY, IN A DIRECTION TRANSVERSE TO SAID FIRST BEARING EDGE TO MAINTAIN SAID STRAIGHT SIDE ENGAGED WITH SAID SIDE SURFACE OF SAID PROJECTION, SAID ELECTROMAGNET BEING OPERATIVE TO PIVOT SAID ARMATURE TO SAID ENERGIZED POSITION; AND RESILIENT STOP MEANS, SAID STOP MEANS BEING SO CONSTRUCTED AND ARRANGED AS TO RESILIENTLY OPPOSE THE PIVOTAL BIASING EFFECT OF SAID RESILIENT MEANS WHEN SAID ARMATURE IS IN SAID DEENERGIZED POSITION, SAID FIRST BEARING EDGE AND SAID POLE PIECE BEING SO DISPOSED THAT, WHEN SAID ARMATURE IS IN SAID ENERGIZED POSITION, SAID SECOND BEARING EDGE IS ENGAGED WITH SAID SIDE SURFACE OF SAID PROJECTION AND IS IN AT LEAST SUBSTANTIAL ALIGNMENT WITH SAID FIRST BEARING EDGE. 